install_precommit_guard · MCP Agent Mail MCP: Risk & Policy

WHAT IT DOES

What install_precommit_guard does on MCP Agent Mail

AI agents invoke install_precommit_guard to trigger actions in MCP Agent Mail. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why install_precommit_guard needs a policy

The name suggests installing a pre-commit guard, which would involve executing system-level operations to set up git hooks or similar mechanisms. However, the description is empty, which significantly lowers confidence.

From the tool's definition Tool name 'install_precommit_guard' suggests installing/setting up a pre-commit hook or guard mechanism, which implies executing an installation operation that modifies system configuration.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

install_precommit_guard Rate-limited

install_precommit_guard stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "install_precommit_guard": {
      "limits": [
        {
          "counter": "install_precommit_guard_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches MCP Agent Mail, so you can run agents against it safely.

FAQ

Questions about install_precommit_guard

What does the install_precommit_guard tool do? +

install_precommit_guard. It is categorised as a Execute tool in the MCP Agent Mail MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on install_precommit_guard? +

Register the MCP Agent Mail MCP server in PolicyLayer and add a rule for install_precommit_guard: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches MCP Agent Mail. Nothing to install.

What risk level is install_precommit_guard? +

install_precommit_guard is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit install_precommit_guard? +

Yes. Add a rate_limit block to the install_precommit_guard rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block install_precommit_guard completely? +

Set action: deny in the PolicyLayer policy for install_precommit_guard. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides install_precommit_guard? +

install_precommit_guard is provided by the MCP Agent Mail MCP server (omelchmichael/mcp_agent_mail). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.